Liquid-poor power circuit breaker

ABSTRACT

The liquid-poor power circuit breaker has a vertical pole column composed of a metallic mechanism housing, a switching chamber above the housing, and a metallic switching head on top of the chamber. A circulatory system for quenching liquid includes a thin insulating tube between the switching head and the mechanism housing outside of the switching chamber. A slider coupled with the movable switch pin of the power breaker blocks the insulating tube when the switch pin is in the break position.

United States Patent 2,909,633 10/1959 Umphrey 200/150G FOREIGN PATENTS1,145,488 5/1957 France ZOO/ 150 B 1,281,324 12/1961 France ZOO/150 B1,381,892 11/1964 France 200/150 B Primary ExaminerRobert S. MaconAll0rneysCurt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel .11 Tick 'A BSTRACT: The liquid-poor power circuitbreaker has a vertical pole column composed ofa metallic mechanismhousing, a switching chamber above the housing, and a metallic switchinghead on top of the chamber. A circulatory system for-quenching liquidincludes a thin insulating tube between the switching head and themechanism housing outside of the switching chamber. A slider coupledwith the movable switch pin of the power breaker blocks the insulatingtube when the switch pin is in the break position.

PATENIEU NUV3OI97I m V Y m LIQUID-POOR POWER CIRCUIT BREAKER Ourinvention relates to a liquid-poor power circuit breaker having avertical column composed of a metallic mechanism housing, a switchingchamber above the housing, and a metallic switch head on top of theswitching chamber. The circuit breaker is provided with a circulationsystem for circulating quenching-liquid by thermosyphon action. Theswitching head and the mechanism housing are connected outside of theswitching chamber by means of a thin tube made of insulating material,the tube being thin in relation to the switching chamber. The tubeenables the circulation system to include a path outside of theswitchingchamber. This arrangement enables a cooling action to beachieved so that the breaker may be installed with a single switchingchamber, that is, without parallel switching chambers, to accommodatethe largest rated current in the mid and high voltage area up to thepresent time.

It is an object of our invention to improve the aforementioned circuitbreaker to increase the switching power of the breaker without having acorresponding deficiency in the cooling action. Subsidiary to thisobject it is an object of our invention to provide such a circuitbreaker which is not appreciably more expensive to produce.

According to a feature of the invention, the insulating tube connectingthe switching head with the mechanism housing is blocked by a sliderwhen the switch pin of the circuit breaker moves to open the latter, theslider being coupled with the movable switch pin.

With the circuit breaker according to the invention, during the closedposition of the breaker, the liquid circulation system stands availablefor cooling when the current flowing through the circuit breakerintroduces heat losses. First in the open circuit condition position isthe liquid circulation produced by thermosyphon action interrupted. Inthis instant, the interior of the switching chamber can be viewed as asealed space wherein the light arc or a mechanical pumping action candevelop the pressure necessary to extinguish the are without requiring apressure balance via the insulating tube serving for cooling purposes.

The slider control with a slider coupled with the switching pin requiresonly a small expense as will be made clear below. Therefore, the instantarrangement is still more practical than a circuit breaker provided withrecoil valves at the beginning and end of the insulating tube. Suchvalves are relatively sensitive with large through passage crosssections and small pressure differences that cause the valves to close.

According to another feature of the invention, the slider member isarranged at the lower portion of the insulating tube and is directlyconnected with the switching pin. By direct is meant that no connectionis provided that influences the movement relationship of the slider andthe switch pin. The slider makes the same movement as does the switchingpin. A covering over of the upper end of the insulating tube can in mostinstances be dispensed with since this opening lies in the vicinity ofthe switching head of the circuit breaker, so that at this location nosignificant overpressure is to be expected which could damage theinsulating tube.

Preferably and according to another feature of the invention the slideris configured as a tubular member having a bore which works togetherwith a bore of the mechanism housing. Preferably and according toanother feature of the invention the slider is configured as a tube ofwhich one end is connected to the insulating tube and which works incooperative relation with a bore of the mechanism housing. The mechanismhousing is then used as a portion of the arrange ment needed forblocking the flow of liquid. This is achieved by arranging theconnecting bore joining into the insulating tube so as to open into abore corresponding to the cross section of the tube used as a slider.The control of a passage of sufficiently large cross section with asmall movable mass is achieved with a slider. In addition the quenchingliquid issuing from the insulating tube can be directed to the lowerportion of the mechanism housing. In this manner the deepest portions ofthe circuit breaker that participate in developing heat are reached withcooled quenching liquid without the necessity of bringing the insulatingtube to the deepest location of the mechanism housing.

The invention will now be described with reference to the drawing whichillustrates the liquid-poor power circuit breaker of the invention.

The drawing illustrates one pole of a liquid-poor power circuit breakerfor medium voltage for example 10 kw. and 4000 A. rated current and isusually constructed as a three-pole assembly. Each pole has a polecolumn that is vertically positioned and is provided with supportinginsulators for mounting on an actuating housing; the latter is notillustrated in the drawing. The pole columns have a metallic mechanismhousing 1. A driving shaft 2 is borne within the housing 1 and passesliquidtight trough the metallic housing. The drive shaft is coupled witha hollow switch pin 5 by a crank 3 and link member 4. The switch pin 5is in electrical connection with the current lead-in rods 7 via contactroller pairs 6.

Above the mechanism housing is disposed a switching chamber 10. lnaddition to the already mentioned switching pin 5, the switching chamber10 contains a fixedly positioned switching member 11. The insulatingportions 12 and 13 are mounted on the wall of the switching chamber 10and function to direct the oil required for quenching the light are thatoccurs when the circuit breaker opens, the pole column being filled withthis oil. The foregoing is described for example in the SIEMENSZEITSCHRIFI volume 38, Apr. 1964, No. 4, pages 229 to 231.

On top of the switching chamber 10 is secured a switching head 15. Thefixedly mounted switching member 11 is connected with the switching head15 via a star-shaped carrier 16. The current flows via carrier part 16to a not illustrated connection surface on the switching head 15. Asimilar connecting surface on the mechanism housing is connected withthe switching pin 5 via the current lead-in rod 7.

A metal elbow 20 is secured to the switching head 15 and has bores whichrun toward each other at right angles; one bore 21 communicates with theswitching head 15 while the other bore communicates with a tube 22 madeof insulating material. Tube 22 is spatially disposed parallel to theswitching chamber 10 and ends in an elbow member 23 that is configuredlike the elbow 20 and is connected to a bore 24 of the mechanism housing1.

The bore 24 functions in cooperative relation with a tubular body 26 asa slider on the inner side of the mechanism housing 1, the slider beingmovable in a direction parallel to the switching pin 5 with theassistance of a guide 27. The tubular body 26 is starlike coupled with aguiding member 28 through the assistance of two attachments. The guidemember 28 is screw connected to the switching pin 5 and constitutes themounting location for the linking member 4.

The tubular body 26 together with the wall of the mechanism housing inthe region of the bore 24 controls the circulation of the quenchingliquid through the tube 22, the liquid serving to cool the circuitbreaker. For the closed position of the switching pin 5 as illustratedin the drawing, the quenching medium heated by means of the heat lossesin the circuit breaker can enter the tube 22 from the switching head 15in the direction of the arrow 30. The quenching liquid is cooled in theinsulating tube 22 because in this region no heat can be developed,whereas, the heat given off to the air surrounding breaker is muchstronger than the heat imparted to the switching chamber itself. Thisoccurs among other reasons because the diameter of the insulating tube22 is substantially smaller than the diameter of the switching chamber.In the illustrated embodiment the insulating tube diameter is only aboutone-quarter of the switching chamber diameter.

The cooled quenching liquid flows in the direction of the arrow 31 atthe bottom end of the insulating tube 22 through bore 24 and acorresponding opening 32 of the tube member 26 in the lower portion ofthe mechanism housing. The tube member 26 directs the cooled liquid tolocations beneath the bore 24 from where the quenching liquid can againtravel upwardly with increasing heat along the current passoverlocations between the switching pin 5 and the current lead-in rods 7.Through slits 33, the quenching medium also passes between theinsulating members 12 and 13 of the quenching chamber as indicated byarrow 34 as well as into the bore 35 of the switching rod 5. The coolingliquid flows further around the fixedly positioned switching member 1]as indicated by arrow 37 as well as through the switching member asshown by arrow 36 until the warm quenching medium is a region of bore 21of the switching head 15.

When the circuit breaker is opened, the tube body 26 moves downwardlydirectly and simultaneously with the switching pin 5. Therefore, thebore 24 in the mechanism housing is closed before the point of theswitching rod leaves the fixedly position switching member 11. Now theswitching pin 5 extending further into the mechanism housing can developa pressure that causes a flow of the quenching liquid through the boreof the switching rod 5 and into the switching head. When the light arcis formed, the pressure developed by the quenching liquid decomposed bythe arcing action can effectively act in the same direction.

The circulation of fluid is checked in the open circuit position of thecircuit breaker of the illustrated embodiment. By means of appropriateopenings in the upper region of the tube body, the circulation of thecooling medium in the open circuit position of the breaker can berenewed in the lower portions of the tube body 26 and the switching pin5.

In the illustrated embodiment only one tube 22 is illustrated for thecirculation of the quenching medium serving also as a cooling liquid,the circulation being controlled by a single tube body 26. The circuitbreaker of the invention can also be configured so that with a singletube body 5, the lower connections of several insulating tubes arrangedparallel to the switching chamber can be controlled on a mechanismhousing. In addition, a switching chamber can be provided with severalparallel insulating tubes wherein each tube has it own slider.

To those skilled in the art, it will be obvious upon a study of thisdisclosure that our invention permits of various modifications withrespect to features and hence, that the invention may be givenembodiments other than particularly illustrated and described hereinwithout departing from the essential features of the invention andwithin the scope of the claims annexed hereto.

We claim:

1. Liquid-poor power circuit breaker comprising a vertical pole columnhaving a metallic mechanism housing, a switching chamber above saidhousing and a metallic switch head supported above said switchingchamber, circulation means for providing a quenching liquid circulationby thermosyphon action, an insulating tube which is thin in comparisonwith said switching chamber and which connects said switch head withsaid mechanism housing outside of the switching chamber, said tubeforming part of said circulation means, a slider for selectivelyblocking and opening said tube, circuit interrupting means disposed insaid switching chamber and comprising an axially displaceably switchpin, said slider being coupled with said switch pin to block said tubewhen said switch pin is in circuit breaking position.

2. Power breaker according to claim 1, said slider being arranged at thelower end of said insulating tube and being directly connected with saidswitch pin.

3. Power breaker according to claim 1, said slider being a tubularmember and said mechanism housing having a bore in communication withsaid tubular slider, said insulating tube having one end connected tosaid housing bore.

4. Power breaker according to claim 3, said tubular slider forming acommunication for the quenching liquid between the insulating tube andthe bottom portion of said mechanism housing.

1. Liquid-poor power circuit breaker comprising a vertical pole columnhaving a metallic mechanism housing, a switching chamber above saidhousing and a metallic switch head supported above said switchingchamber, circulation means for providing a quenching liquid circulationby thermosyphon action, an insulating tube which is thin in comparisonwith said switching chamber and which connects said switch head withsaid mechanism housing outside of the switching chamber, said tubeforming part of said circulation means, a slider for selectivelyblocking and opening said tube, circuit interrupting means disposed insaid switching chamber and comprising an axially displacable switch pin,said slider being coupled with said switch pin to block said tube whensaid switch pin is in circuit breaking position.
 2. Power breakeraccording to claim 1, said slider being arranged at the lower end ofsaid insulating tube and being directly connected with said switch pin.3. Power breaker according to claim 1, said slider being a tubularmember and said mechanism housing having a bore in communication withsaid tubular slider, said insulating tube having one end connected tosaid housing bore.
 4. Power breaker according to claim 3, said tubularslider forming a communication for the quenching liquid between theinsulating tube and the bottom portion of said mechanism housing.